First, before we even can start, many organs are not tuned "wohltemperiert". They are tuned harmonic from a certain starting point. This means we have to have a simple midi command or a table where we can change the frequency for every note.
Otherwise we would have problems to simulate many existing organs. More you'll find here (in german): http://members.aol.com/ReinerJank/home-de.htm At this time I wont elaborate this and first concentrate on harmonics. In past I mentioned that it will be useful (no, its imperative!) to have a harmonic generator. This comes more than true if we try to simulate organs. Because organs are really harmonic simulators. Some thoughts about this to start: I assume the lowest frequencys man can hear is around 15 Hz, some organs even go below that, but lets start here. The highest are around 20 kHz. We count the ocataves that are: 1 - 15 2 - 30 -2 3 - 60 -4 4 - 120 -8 5 - 240 -16 6 - 480 -32 7 - 960 -64 8 - 1920 -128 9 - 3840 -256 10- 7680 -512 11-15360 -1024 12-30720 -2048 Thats 12 ocataves. In harmonics thats from the second up to the 2000th harmonic max that are relevant. Its not that much what we need, I just wanted to make a point for calculations. But with control over 2000 harmonics we'd be able to build every possible simple (unchanging) sound through additive synthesis. The upper harmonics usually are configured through the SOUND of the pipe. You can build pipes with soft sounds with hard sounds with or without much harmonics or with "gedackte" pipes you kill all even harmonics (sounds a bit more like rectangle, trapez -a triangle with atan-distortion- or something like this, I'd presume). Easy going. This is by the way the (yet poor) possibilities in the dav-module tries to do this. "brass", "flute" and "reed" - thats not enough. We have to put in there a vast number of possible waveforms, maybe we calculate them to simulate roughly the sound of certain pipes. But first back to harmonics. For organs we seldom need more than control over 10-15 harmonics (for real organs there are certain mechanical limits) and I tell you now which are the most used. Basetone 1 (8" = prinzipal) Octave 1/2 (4") 1/4 (2") 1/8 (1") 1/16 (1/2") Quint 1/3 (2 2/3") 1/6 1/9 (8/9" - "None") 8/3 (21 1/3") - deeeeper, only pedals 4/3 (10 2/3") - even deeper than Gross Nasard, only on pedals 2/3 (5 1/3") - only in great organs "Gross Nasard" 2/9 Terz 1/5 (1 3/5") 1/10 2/5 (3 1/5") (Grosse Tierce) Sept 1/7 (1 1/7") 1/14 2/7 (2 2/7") None 1/9 (8/9" see Quint) 2/9 (1 7/9") Higher harmonics 1/11 (8/11") undezime 2/11 (1 5/11") tredezime (only pedals) 1/13 (8/13") quindezime 1/15 (8/15") see Terz 1/17 (16/17") kleine Sekunde (only pedals) 1/19 (16/19") reine Mollterz (only pedals) Inharmonics 9/40 (1 4/5") moll Terz With this we have more or less all harmonics most organs will do. If I forgot one, we have to fix that. Some of the tones only make sense on deeper frequencys, but with this the organ module would be much more rounded up. I will fire more about organs next. When I have more about making special sounds. The pipes in the registers will create sometimes harmonics itself, sometimes they only play more or less sinewavs. That one I will specify more precisely in future. hope that helps Hanno _______________________________________________ beast mailing list [email protected] http://mail.gnome.org/mailman/listinfo/beast
